This fall, I found out what that phrase really means when I signed up to compete in my first real marathon. On a brisk morning, just before 7 a.m., with Eminem’s “Lose Yourself” blasted over the loudspeakers, I crossed the starting line and headed out onto the streets of Detroit in my 26.2-mile quest.

The story of the marathon's origins is widely circulated among the running community. As legend has it, the Greek messenger Pheidippides ran the 26.2-mile road to Athens after the Greeks defeated the invading Persians at the Battle of Marathon in 490 B.C.E.

After proclaiming the good news to the city’s assembly, Pheidippides collapsed and died. Today, more than half a million people per year complete marathons in the U.S., competing in well over 1,000 events nationwide.

Everyone knows that marathons are long, but it’s hard to understand just how long until you complete one. Median finishing times are about 4:16 for men and 4:41 for women. That’s over four hours of moderate to severely strenuous physical activity — enough to inflict serious damage on the bodies of even the most seasoned athletes.

In no uncertain terms, let me say that I am not a seasoned athlete. I am, however, a neuroscience major currently enrolled in courses covering animal physiology and cell biology, and this is my leg-up on Pheidippides.

Modern marathoners begin training programs months in advance of race-day, slowly building up miles and allowing their bodies to adjust to the strain of high-mileage running. For my October race, my first training run — a two-mile jog around my neighborhood — took place in May.

It takes approximately four to six weeks for bone and muscle to adjust to the load of running impacts. While this makes for an unpleasant start to marathon training — indeed, the reason many individuals fail before they start — the gains made in early months pay massive dividends later on.

But the body is just a vehicle for runners. In order to successfully run a marathon, you need energy — namely glycogen derived from carbohydrates consumed before the race. The problem for runners is that the average human only stores enough glycogen to run half the distance of a marathon.

This results in the lengthy process of “carb-loading” during training and in the days leading up to the race, essentially tricking your body into taking on more fuel than it would need for any normal activity.

Such understanding of human physiology is the result of decades of research by doctors, athletic trainers, nutritionists and athletes. In my preparations, I benefited from their work and successfully completed my first marathon while avoiding the Pheidippides’ ultimate fate.

Clocking a time of about 4:30, I was nowhere near the top of the standings, but having never run a competitive race in my life, knowing that I had the ability to even finish was reward enough. All it required was planning and determination (and a little bit of science).